3(54 AGRICULTURE [ROOT CROPS. CHAPTER XII. CULTIVATED CROPS ROOT CROPS. Section 1. Potato. The events of late years render it necessary to regard this root somewhat differently than was warranted by its previous history. Its value as an article of food, relished alike by prince and peasant, its easy culture, its adaptation to a very wide diversity of soil and climate, and the largeness of its produce, justly entitled it to the high esteem in which it was universally held. Like many other good gifts, it was, however, grossly abused, and diverted from its legitimate use ; and advantage was taken of its amazing productive powers to elevate it from the place of an agreeable, wholesome addition to the daily food of the community to that of " the staff of life." In Ireland and the Highlands of Scotland, the people, already in a pain fully degraded condition, and contented with the potato as their sole food all the year round, took occasion, from its very productiveness, under the rudest culture, to sub divide their lands, and marry prematurely, with reckless improvidence, and amid an ever-deepening degradation. We know now, from the utter prostration and helplessness into which this wretched population was at once thrown by the memorable potato disease, the terrible penalty which this abuse of " a good gift" has brought directly on the miserable sufferers, and indirectly on the whole com munity. It will be well if the stern lesson, enforced by famine and pestilence, have the effect of leading to a better social condition. Viewed in this light, the potato disease may yet prove a blessing to the nation. Its continued prevalence, although in a mitigated form, cannot well be regarded otherwise, when we remember the frantic eagerness with which the Irish peasantry replanted their favourite root on the first indication of its returning vigour, and the desperate energy with which they cling to it under repeated disappointments. Apart from this speciality, the precarious health of this important esculent is much to be regretted. It seems contrary to analogy to suppose that it is likely either to be entirely lost or to manifest a permanent liability to disease. It seems more natural to suppose that by-and- by the disease will disappear, or that some efficient remedy for it will be discovered. Railways afford great facilities for transporting this bulky commodity at little expense to great distances, and thus render the market for it available to a wider district. Apart from disease, this facility of transport would naturally insure its more extended cultiva tion. This enlarged cultivation of a crop which, to be grown successfully, requires a soil rich in fertilising matters, has moreover been rendered practicable by the facilities which the farmer now has of obtaining guano and other portable manures. The varieties of the potato, whether for garden or field culture, are exceedingly numerous, and admit of endless increase by propagating from seeds. It would serve no useful purpose to enumerate here even a selection from the sorts in use in different parts of the country. In Messrs Lawson s Synopsis of the Vegetable Products of Scotland a description of 175 kinds is given, to which the reader is referred for particulars. When the crop is grown for cattle food, bulk of produce will be the primary consideration; but for sale or family use, flavour, keeping quality, and handsome appearance, will be particularly attended to. Exemption from disease is now a momentous consideration, whatever the use for which it is grown. There is this difficulty, however, connected with selections on the score of healthiness, that while in each season since the disease broke out certain varieties have escaped, it is observed from year to year that the exempted list varies, certain kinds that had been previously healthy becoming as obnoxious to disease as any, and others in a great measure escaping that had suffered much before. Indeed, certain parties, from observing that diseased tubers left in the ground have produced healthy plants in the following season, have been induced purposely to plant diseased potatoes, and with good results. This, however, is probably due to the mere fact of their being kept in the earth. In field culture the potato is frequently grown on a portion of the fallow break ; but its appropriate place in the rotation is that usually assigned to beans, with which, in an agricultural point of view, it has many features in common, and in lieu of which it may with advantage be cultivated. As the potato requires to be planted as early in spring as the weather will admit of, thus leaving little opportunity for cleaning the land, and as its mode of growth forbids any effective removal of root-weeds by after culture, it is peculiarly necessary to have the land devoted to this crop cleaned in autumn. Winter dunging facilitates the planting, and is otherwise beneficial to the crop by producing that loose and mellow condition of the soil in which the potato delights. The quality of the crop is also believed to be better when the dung is thoroughly incor porated with the soil, than when it is applied in the drill at the time of planting. A liberal application of manure is necessary if a full crop is expected. The rank growth thus induced renders it, however, more obnoxious to the blight, and hence at present it is more prudent to aim rather at a sound crop than an abundant one, and for this purpose to stint the manure. When it is applied at the time of planting, the mode of procedure is the same as that which will presently be described in the section on turnip culture. The potato sets are prepared a few days before they are expected to be needed. Tubers about the size of an egg do well to be planted whole ; and it is a good plan to select these when harvesting the crop, and to store them by themselves, that they may be ready for use without further labour. The larger tubers are cut into pieces having at least one sound eye in each, although two are better. It is of great consequence to have seed-potatoes stored in a cool and dry pit, so that if possible they may be prepared for planting before they have begun to shoot. If there has been any heating in the pit, the potatoes are found to be covered by a rank crop of shoots, which are necessarily rubbed off, and thus the most vigorous eyes are lost, and much of the substance which should have nourished the young plant is utterly wasted. A sufficient number of dormant eyes are no doubt left, but from the comparatively exhausted state of the tubers, these produce stems of a weaker and more watery character, and more liable to disease than those first protruded. To avoid these evils, gardeners are at pains to invigorate their seed potatoes and husband their whole powers for early and vigorous growth by greening them in autumn, storing them in a cool place with a current of air passing through it, and then in early spring exposing them to light on a floor, whence they are carefully removed and planted with their short green shoots unbroken. Neither the greening nor the sprouting under cover and in the light can ordinarily be practised on the scale on which the field culture of the potato is conducted. But the important feature in it, viz., so treating potatoes intended for seed that the crop shall be produced from the first and most vigorous shoots, and that these shall obtain the full benefit of the natural pabulum stored up for their use in the parent tuber, should be care fully considered and imitated if possible in field culture. The report of the meeting of the Edinburgh Botanical Society, on 8th January 1852, bears that "Professor Simpson communicated the results of some experiments made by himself and Mr Stewart relative to the growth of
alpine plants after having been kept artificially covered
